Hydroentangling or spunlacing is a technique introduced during the 1970'ies, see e.g. CA 841,938. The method involves forming a fibre web which is either drylaid or wetlaid, after which the fibres are entangled by means of very fine water jets under high pressure. Several rows of water jets are directed against the fibre web which is supported by an entangling member in the form of a movable wire or a perforated rotatable drum. The entangled fibre web is then dried. The fibres that are used in the material can be synthetic or regenerated staple fibres, e.g. polyester, polyamide, polypropylene, rayon or the like, pulp fibres or mixtures of pulp fibres and synthetic staple fibres. Spunlaced materials can be produced with high quality to a reasonable cost and have a high absorption capacity. They can e.g. be used as wiping material for household or industrial use, as disposable materials in medical care and for hygiene purposes, etc.
Through EP-B-333,211 and EP-B-333,228 it is known to hydroentangle a fibre mixture in which one type of fibres is meltblown fibres. The polymers used for the continuous filaments are mostly polyolefins, especially polypropylene and polyethylene, or polyethylene terephtalate, polybutylene terephtalate, polyvinyl chloride etc. The base material, i.e. the fibrous material which is exerted to hydroentangling, either consists of at least two preformed fibrous layers, where one layer is composed of meltblown fibres or of a “coformed material”, in which an essentially homogeneous mixture of meltblown fibres and other fibres is airlaid on a wire.
Through EP-A-308,320 it is known to bring together a web of bonded continuous filaments with wetlaid fibrous material containing pulp fibres and staple fibres. The separately formed fibrous webs are hydroentangled together to form a laminate. In such a material the fibres of the different fibrous webs will not be well integrated with each other since the continuous fibres are pre-bonded. This pre-bonding of the continuous filament will during the hydroentangling procedure limit the mobility and thereby result in a material with limited integration.
Through WO 92/08834 it is known to air-lay staple fibres on a forming wire and on top thereof air-lay defibrated pulp fibres. The formed fibrous web is then subjected to three steps of hydroentanglement. In the first step the web is hydroentangled against a fine-mesh wire and is then transferred to coarse-mesh screen on which it is exerted to a second hydroentangling. In this second hydroentangling step the water jets will press loose fibre ends through the coarse meshes in the wire. The web is then transferred to a third fine-mesh wire and hydroentangled a third time in order to ensure that those loose fiber ends will be folded against the fine-mesh wire and be intertwined and firmly secured to the web. This is told to produce a spunlace material having a high wear resistance.
Through U.S. Pat. No. 5,459,912 it is known to make patterned spunlace materials comprising woodpulp fibers and synthetic fibers. The synthetic fibers may be in the form of textile staple fibers or spunbonded fibers. The spunbonded fibers are in the form of a spunbonded web of filaments, which means that the filaments are thermally bonded to each other and cannot move and integrate with the other fibers during the hydroentangling.
WO 99/20821 discloses a method of making a composite nonwoven material, wherein a fibres and a web of continuous filaments, such as a spunbond or meltblown web, are hydroentangled, a bonding material is applied to the web, which is subsequently creped. Again the web of continuous filaments is a web wherein the filaments are bonded to each other.
Through EP-B-938,601 it is known to bring together a web of continuous filaments with foam formed fibrous material containing pulp fibres and synthetic staple fibres. The resulting web is then hydroentangled together to a composite material in one hydroentangling step. The continuous filaments are substantially free from each other before hydroentangling and the resulting material will show an integration between the foam formed material and the continuous filaments.
There is however still room for improvements especially with respect to hydroentangled materials having a patterned and/or apertured structure and a good integration between continuous filaments and other fibers contained in the web.